This question has come up a few times lately…many of us have been taught that sheetrock/drywall/wallboard has to penetrate at least 1/2 inch behind the returns on a fire-rated frame, but where is that stated?
I found the graphic below in NFPA 80 (all recent editions) with a line in Annex A stating that frames should be installed following the general guidelines shown in this figure. These details don’t cover all applications, and there are some additional details in NFPA 80 which show frames butted to existing walls, without wrapping the GWB. When in doubt, check with the frame manufacturer to see what is allowed by their listings (and refer to this post regarding existing wall anchors).
I also asked UL what is stated in their requirements, because of an architectural detail in question, which showed one layer of GWB penetrating the frame on each side of the wall, and a second layer butted to the frame. The representative from UL said that having the frame wrap one layer on each side is acceptable, and the additional wall finish is not required to be wrapped by the frame.
As one of the commenters on this post mentioned, if the rating of the wall requires two layers of GWB on one or both sides, there should not be a gap between the end of the second layer of GWB and the return on the frame, as this leaves a space with less protection than what is required. I have worked on several projects where the architect wanted a “shadow gap” (AKA “shadow line”) around the frame (like this). In some cases, a special frame profile with a couple of extra bends may be needed so the extra layer of GWB can butt up to the custom return while maintaining the aesthetic shadow gap.